The lack? The presence of bruising of the external labia, is what the autopsy reveals.
Moreover, she had over 30+ further bruises.
Sorry, but this is both incorrect and intentionally misleading.
Firstly, this is what the Massei report had to say on the condition of Meredith's genitals post-mortem, according to the autopsy report:
Following divarication of the major and minor lips (i.e. labia), it was possible to note small areas of bruising, coloured darker than the surrounding areas. The hymen was indented without any lacerations or traumatic injuries, indicating that the young woman was sexually active. Nor did the vaginal canal or the cervix present injuries "of any pathological or traumatic significance"
Taken as a whole, it's absolutely clear that the autopsy report found no
traumatic injury to Meredith's genitals. The labia tend to be prone to small contusions during normal sex, since they are stretched and abraded by normal intercourse. As the autopsy report clearly states, there was no other indicator other than that "the young woman was sexually active".
Secondly, it's obviously time once more to dispel this pro-guilt myth about the amount (and implied severity) of marks and bruises found on Meredith's body at autopsy. In fact, excluding the head and neck, there were virtually no significant marks or bruises present. Again, quoting from the Massei report's summery of the autopsy report:
There were no noticeable injuries to the chest or abdomen.
The presence of two relatively slight areas of bruising, with scarce colouring and barely noticeable, were detected in the region of the elbow.
On the hands were small wounds showing a very slight defensive response.
A small, very slight patch of colour was noticed on the "anterior inner surface of the left thigh" (page 16). Another bruise was noted on the anterior surface, in the middle third of the right leg" (page 17).
AND THAT'S IT: "No noticeable injuries to the chest or abdomen"; "two relatively slight areas of bruising, with scarce colouring and hardly noticeable" around the elbow; "small wounds" on the hands; a"small. very slight patch of colour" on the inside front of the left thigh; another bruise on the front middle of the right leg.
And that's it.
These injuries are simply not compatible with forced restraint against a victim who is struggling against that restraint. They are, however, completely compatible with the victim having been essentially put into submission through threats, with someone lightly holding her elbows at one point, and a very small defensive response by the victim against a knife held at her throat (which in itself suggests that her hands were not being held down at the time).
Simply put, Meredith Kercher was not covered in significant marks and bruises. Ergo, she did not become involved in any kind of violent struggle with any attacker (or attackers), and nor was she violently restrained at any time.